A hearing aid is an electronic device known to alleviate hearing loss of a human. Generally, the hearing aid captures sounds from the environment using one or more microphones and amplifies the captured sounds electrically according to a hearing aid prescription. Digital representations of the amplified signals are converted back into electrical signals suitable for driving an output transducer of the hearing aid for generating sound waves perceivable to its user.
It is known to utilize a battery to power a hearing aid. Zinc-air batteries, while characteristic of a high energy density and relatively inexpensive to produce, are non-rechargeable and must be replaced once they have been depleted. A silver-zinc battery is capable of being recharged but includes a higher maximum voltage compared to that of the zinc-air battery. For instance, the zinc-air battery may include a maximum voltage of about 1.45 V and the silver-zinc battery may include a maximum voltage of about 1.86 V. This maximum voltage corresponding to the silver-zinc battery may exceed voltage thresholds of existing electronics within the hearing aid. Accordingly, the silver-zinc battery cannot simply be utilized as a substitute for the zinc-air battery unless the maximum voltage is lowered or the electronic components within the hearing aid are redesigned.
A rechargeable hearing aid is required to be turned off and unpowered to avoid draining the battery during charging events and prevent feedback noise or whistling from occurring while the battery of the hearing aid is connected to a charger. Generally, the rechargeable hearing aid utilizes designated external contacts for charging the battery. There is only enough to room to utilize two external contacts, e.g., a charger positive voltage and a charger negative voltage, due to the very small size of the hearing aid. Accordingly, an additional external contact indicating a charger present signal is not available for use to turn off the hearing aid during the charging event.